Citation and License

Nutrition Journal 2012, 11:105
doi:10.1186/1475-2891-11-105

Published: 11 December 2012

Abstract

Background

Excess adipose tissue and sarcopenia presents a multifaceted clinical challenge that
promotes morbidity and mortality in the obese, elderly population. Unfortunately,
the mortality risks of muscle loss may outweigh the potential benefits of weight loss
in the elderly. We have previously demonstrated the effectiveness of whey protein
and essential amino acids towards the preservation of lean tissue, even under the
conditions of strict bedrest in the elderly.

Methods

In the context of caloric restriction-based weight loss, we hypothesized that a similar
formulation given as a meal replacement (EAAMR) would foster the retention of lean
tissue through an increase in the skeletal muscle fractional synthesis rate (FSR).
We also proposed that EAAMR would promote the preferential loss of adipose tissue
through the increased energy cost of skeletal muscle FSR. We recruited and randomized
12 elderly individuals to an 8 week, caloric restriction diet utilizing equivalent
caloric meal replacements (800 kcal/day): 1) EAAMR or a 2) competitive meal replacement
(CMR) in conjunction with 400 kcal of solid food that totaled 1200 kcal/day designed
to induce 7% weight loss. Combined with weekly measurements of total body weight and
body composition, we also measured the acute change in the skeletal muscle FSR to
EAAMR and CMR.

Results

By design, both groups lost ~7% of total body weight. While EAAMR did not promote
a significant preservation of lean tissue, the reduction in adipose tissue was greater
in EAAMR compared to CMR. Interestingly, these results corresponded to an increase
in the acute skeletal muscle protein FSR.

Conclusion

The provision of EAAMR during caloric restriction-induced weight loss promotes the
preferential reduction of adipose tissue and the modest loss of lean tissue in the
elderly population.